1. Field of the Invention
This invention relates to hand-held optical reading devices and, more particularly, to hand-held readers or wands used in conjunction with a processing unit such as a character recognition processing apparatus.
2. Prior Art
Systems for optically reading alpha-numeric characters commonly utilize hand-held readers or wands (hereinafter these terms are used interchangeably) which are manually passed or scanned over the field of printed characters to be read. It is necessary in these systems that the wand be aligned within known tolerances during the scanning or wanding process with respect to the character field in order to insure that the characters are accurately read. Reading errors will occur, for example, if the path of wand travel is severely skewed or the wand is tilted or twisted during the wanding process.
U.S. Pat. No. 3,947,817 discloses a system which provides compensation for reading errors caused by the misalignment of hand-held wands. The system incorporates electronic processing means which permits reading despite some misalignment between the wand and the character field during the wanding process. However, even with such system, the operator must take reasonable care to align the wand with the characters since the amount of compensation provided by the system is limited.
The present invention is directed to a wand which allows the operator to provide "mechanical" alignment between the wand and characters. The disclosed wand may be used with a character recognition system which also provides electronic compensation means for correcting for misalignments which remain.